Bjørn Fredrik Nielsen

Publication Activity (10 Years)

Years Active: 1996-2024
Publications (10 Years): 9

Top Topics

Partial Differential Equations

Total Variation Regularization

Differential Operators

Sparsity Regularization

Top Venues

SIAM J. Numer. Anal.

Numer. Algorithms

Publications

Bjørn Fredrik Nielsen, Zdenek Strakos
A Simple Formula for the Generalized Spectrum of Second Order Self-Adjoint Differential Operators. SIAM Rev. 66 (1) (2024)
Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos
Numerical approximation of the spectrum of self-adjoint operators in operator preconditioning. Numer. Algorithms 91 (1) (2022)
Ole Løseth Elvetun, Bjørn Fredrik Nielsen
Box constraints and weighted sparsity regularization for identifying sources in elliptic PDEs. CoRR (2022)
Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos
Numerical approximation of the spectrum of self-adjoint continuously invertible operators. CoRR (2021)
Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos
Generalized Spectrum of Second Order Differential Operators. SIAM J. Numer. Anal. 58 (4) (2020)
Ole Løseth Elvetun, Bjørn Fredrik Nielsen
Sparsity regularization for inverse problems with nullspaces. CoRR (2020)
Tomás Gergelits, Kent-André Mardal, Bjørn Fredrik Nielsen, Zdenek Strakos
Laplacian Preconditioning of Elliptic PDEs: Localization of the Eigenvalues of the Discretized Operator. SIAM J. Numer. Anal. 57 (3) (2019)
Ole Løseth Elvetun, Bjørn Fredrik Nielsen
PDE-Constrained Optimization with Local Control and Boundary Observations: Robust Preconditioners. SIAM J. Sci. Comput. 38 (6) (2016)
Ole Løseth Elvetun, Bjørn Fredrik Nielsen
The split Bregman algorithm applied to PDE-constrained optimization problems with total variation regularization. Comput. Optim. Appl. 64 (3) (2016)
Marius Lysaker, Bjørn Fredrik Nielsen, Samuel T. Wall
Bidomain Simulations of Subendocardial Ischemia: The Forward and Inverse Problems. CinC (2014)
Glenn T. Lines, Marius Lysaker, Bjørn Fredrik Nielsen
Observability of Ischemia and the Need for Patient Specific Geometrical Models in Inverse ECG. CinC (2013)
Bjørn Fredrik Nielsen, Ola Marius Lysaker, Per Grottum
Computing Ischemic Regions in the Heart With the Bidomain Model - First Steps Towards Validation. IEEE Trans. Medical Imaging 32 (6) (2013)
Bjørn Fredrik Nielsen, Kent-André Mardal
Analysis of the Minimal Residual Method Applied to Ill Posed Optimality Systems. SIAM J. Sci. Comput. 35 (2) (2013)
Ola Marius Lysaker, Bjørn Fredrik Nielsen, Samuel T. Wall
Computing Ischemic Regions in the Heart: On the Use of Internal Electrodes. CinC (2013)
Bjørn Fredrik Nielsen, Kent-André Mardal
Efficient Preconditioners for Optimality Systems Arising in Connection with Inverse Problems. SIAM J. Control. Optim. 48 (8) (2010)
Tomas Syrstad Ruud, Bjørn Fredrik Nielsen, Ola Marius Lysaker, Joakim Sundnes
A Computationally Efficient Method for Determining the Size and Location of Myocardial Ischemia. IEEE Trans. Biomed. Eng. 56 (2) (2009)
Kent-André Mardal, Bjørn Fredrik Nielsen, Xing Cai, Aslak Tveito
An order optimal solver for the discretized bidomain equations. Numer. Linear Algebra Appl. 14 (2) (2007)
Bjørn Fredrik Nielsen, Tomas Syrstad Ruud, Glenn Terje Lines, Aslak Tveito
Optimal monodomain approximations of the bidomain equations. Appl. Math. Comput. 184 (2) (2007)
Bjørn Fredrik Nielsen, Marius Lysaker, Aslak Tveito
On the use of the resting potential and level set methods for identifying ischemic heart disease: An inverse problem. J. Comput. Phys. 220 (2) (2007)
Xing Cai, Bjørn Fredrik Nielsen, Aslak Tveito
A note on the efficiency of the conjugate gradient method for a class of time-dependent problems. Numer. Linear Algebra Appl. 14 (5) (2007)
Mary C. MacLachlan, Bjørn Fredrik Nielsen, Ola Marius Lysaker, Aslak Tveito
Computing the size and location of myocardial ischemia using measurements of ST-segment shift. IEEE Trans. Biomed. Eng. 53 (6) (2006)
Aslak Tveito, Bjørn Fredrik Nielsen
On the Approximation of the Solution of the Pressure Equation by Changing the Domain. SIAM J. Appl. Math. 57 (1) (1997)
Are Magnus Bruaset, Bjørn Fredrik Nielsen
On the Stability of Pressure and Velocity Computations for Heterogeneous Reservoirs. SIAM J. Appl. Math. 56 (4) (1996)